Flooding disable

Updated: September 11, 2026

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Explains the flooding disable feature, providing guidance on configuration steps to control unwanted broadcast and unknown traffic within bridge domains.

A flooding disable feature is a bridge-level forwarding control that

prevents forwarding of broadcast, unknown-unicast, and multicast traffic on a bridge domain
can disable flooding of BUM traffic at the bridge level, and
can also disable only unknown-unicast traffic at the bridge level.

Configure flooding at the bridge level

Prevent unwanted traffic flooding within a bridge domain by selectively disabling flooding for BUM (broadcast, unknown-unicast, and multicast) traffic or unknown-unicast traffic.

You can improve network performance and control how traffic is handled by disabling flooding of BUM traffic or unknown-unicast traffic at the bridge domain level. Disabling unknown-unicast flooding only applies when BUM flooding disable is not configured.

Before you begin

Follow these steps to configure either flooding disable behavior.

Procedure

Disable flooding of BUM traffic at the bridge level.

Example:

Router# configure
Router(config)# l2vpn
Router(config-l2vpn)# bridge group bg1
Router(config-l2vpn-bg)# bridge-domain bd1
Router(config-l2vpn-bg-bd)# flooding disable
Router(config-l2vpn-bg-bd)# commit

Disable flooding of unknown-unicast traffic at the bridge level when BUM flooding disable is not configured.

Example:

Router# configure
Router(config)# l2vpn
Router(config-l2vpn)# bridge group bg1
Router(config-l2vpn-bg)# bridge-domain bd1
Router(config-l2vpn-bg-bd)# flooding unknown-unicast disable
Router(config-l2vpn-bg-bd)# commit

Review the running configuration.

Example:

configure
 l2vpn
  bridge group bg1
   bridge-domain bd1
    flooding disable
   !

configure
 l2vpn
  bridge group bg1
   bridge-domain bd1
    flooding unknown-unicast disable
   !
  !

The bridge domain uses the specified flooding-disable setting, effectively controlling network traffic as desired.

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